scoville scale

In the Scoville organoleptic test, an exact weight of dried pepper is dissolved in alcohol to extract the heat components (capsaicinoids), then diluted in a solution of sugar water.{{cite book|last=Peter|first=K. V.|title=Handbook of Herbs and Spices|url=https://books.google.com/books?id=P4FwAgAAQBAJ&pg=PA127|year=2012|publisher=Elsevier Science |isbn= 978-0-85709-5671|page=127}} Decreasing concentrations of the extracted capsaicinoids are given to a panel of five trained tasters, until a majority (at least three) can no longer detect the heat in a dilution. The heat level is based on this dilution, rated in multiples of 100 SHU.

Another source using subjective assessment stated, "Conventional methods used in determining the level of pungency or capsaicin concentration are using a panel of tasters (Scoville organoleptic test method). ... Pepper pungency is measured in Scoville heat units (SHU). This measurement is the highest dilution of a chili pepper extract at which heat can be detected by a taste panel."{{cite journal | vauthors = Collins MD, Wasmund LM, Bosland PW | year = 1995 | title = Improved method for quantifying capsaicinoids in Capsicum using high-performance liquid chromatography | url = http://hortsci.ashspublications.org/content/30/1/137.full.pdf+html | journal = HortScience | volume = 30 | issue = 1 | pages = 137–139 | doi = 10.21273/HORTSCI.30.1.137 | doi-access = free }}{{cite journal|pmid=28662907|year=2017|last1=Guzmán|first1=I|title=Sensory properties of chili pepper heat - and its importance to food quality and cultural preference|journal=Appetite|volume=117|pages=186–190|last2=Bosland|first2=P. W|doi=10.1016/j.appet.2017.06.026|doi-access=free}}{{cite journal

|vauthors=Stoica R, Moscovici M, Tomulescu C, Băbeanu N

|title=Extraction and analytical methods of capsaicinoids - a review

|journal=Scientific Bulletin. Series F. Biotechnologies

|year=2016

|volume=XX

|pages=93–96

|s2cid=38430045

|url=https://pdfs.semanticscholar.org/0b7b/b726c67c316530bc445cdea106c0ad167f6b.pdf

|archive-url=https://web.archive.org/web/20180811102358/https://pdfs.semanticscholar.org/0b7b/b726c67c316530bc445cdea106c0ad167f6b.pdf

|url-status=dead

|archive-date=2018-08-11

|issn=2285-1364

}}

A weakness of the Scoville organoleptic test is its imprecision due to human subjectivity, depending on the taster's palate and number of mouth heat receptors, which vary widely among subjects. Another shortcoming is sensory fatigue; the palate is quickly desensitized to capsaicinoids after tasting a few samples within a short time period. Results vary widely (up to ± 50%) between laboratories.{{cite book |last=Tainter |first=Donna R. |author2=Anthony T. Grenis |year=2001 |title=Spices and Seasonings |publisher=Wiley-IEEE |isbn=978-0-471-35575-5 |url=https://books.google.com/books?id=dfp4b3F0598C&pg=PA30 |page=30|quote= Interlab variation [for the original Scoville scale] could be as high as +/−50%. However, labs that run these procedures could generate reasonably repeatable results.}}

Image:Red savina cropped.jpg, a hot chili{{Cite book |last1=DeWitt |first1=Dave |last2=Bosland |first2=Paul W. |title=The Complete Chile Pepper Book |year=2009 |publisher=Timber Press |isbn=978-0-88192-920-1}}]]

Since the 1980s, spice heat has been assessed quantitatively by high-performance liquid chromatography (HPLC), which measures the concentration of heat-producing capsaicinoids, typically with capsaicin content as the main measure. As stated in one review "the most reliable, rapid, and efficient method to identify and quantify capsaicinoids is HPLC; the results of which can be converted to Scoville heat units by multiplying the parts-per-million by 16."{{efn|name=fifteen-sixteen}}

HPLC method gives results in American Spice Trade Association 1985 "pungency units", which are defined as one part capsaicin equivalent per million parts dried pepper mass. This "parts per million of heat" (ppmH) is found with the following calculation:

$$\backslash text\{ppmH\}\; =\; \backslash frac\{\backslash text\{peak\; area\}(\{\backslash text\{capsaicin\})\}\; +\; 0.82\backslash cdot\; \backslash text\{peak\; area\}(\backslash text\{dihydrocapsaicin)\}\}\{\backslash text\{peak\; area\}(\backslash text\{standard)\}\}$$

Peak areas are calculated from HPLC traces of dry samples of the substance to be tested in 1 ml of acetonitrile. The standard used to calibrate the calculation is 1 gram of capsaicin. Scoville heat units are found by multiplying the ppmH value by a factor of 15.{{Efn|name=fifteen-sixteen|Some sources such as Guzman state a factor of 16 in line with the 16,000,000 SHU figure of pure capsaicin. However, Guzman cites the Collins source. which clearly states 15 per ASTA.}} By this definition of ppmH, spicy compounds other than the two most important capsaicinoids are ignored, despite the ability of HPLC to measure these other compounds at the same time.

Since Scoville ratings are defined per unit of dry mass, comparison of ratings between products having different water content can be misleading. For example, typical fresh chili peppers have a water content around 90%, whereas Tabasco sauce has a water content of 95%.USDA nutrient database for [https://web.archive.org/web/20140517121309/http://ndb.nal.usda.gov/ndb/foods/show/3569?fg=&man=&lfacet=&format=&count=&max=25&offset=&sort=&qlookup=pepper Peppers, jalapeño, raw] (92% water content); [https://web.archive.org/web/20140517121119/http://ndb.nal.usda.gov/ndb/foods/show/3419?fg=&man=&lfacet=&format=&count=&max=25&offset=&sort=&qlookup=pepper Peppers, hot chile, red, raw] (88% water content); [https://web.archive.org/web/20140517120516/http://ndb.nal.usda.gov/ndb/foods/show/1214?qlookup=tabasco&fg=&format=&man=&lfacet=&max=25&new=1 Red Tabasco sauce] (95%) For law-enforcement-grade pepper spray, values from 500,000 up to 5 million SHU have been reported,{{cite web | url = http://www.theppsc.org/Staff_Views/Czarnecki/chemical_hazards_in_law_enforcement.htm | title= Chemical hazards in law enforcement | publisher= The Police Policy Studies Council | access-date = 2009-02-09 | quote = Most law enforcement sprays have a pungency of 500,000 to 2 million SHU. One brand has sprays with 5.3 million SHU.}} but the actual strength of the spray depends on the dilution. This problem can be overcome by stating the water content along with the Scoville value. One way to do so is the "D-value", defined as total mass divided by dry mass.{{cite web |title=Let's Get Technical: The Limitations of the Scoville Scale |url=https://www.joshjungle.com/2017/04/22/2017-4-22-lets-get-technical-the-limitations-of-the-scoville-scale/ |website=Josh's Jungle |date=22 April 2017}}

Numerical results for any specimen vary depending on its cultivation conditions and the uncertainty of the laboratory methods used to assess the capsaicinoid content. Pungency values for any pepper are variable, owing to expected variation within a species, possibly by a factor of 10 or more, depending on seed lineage, climate and humidity, and soil composition supplying nutrients. The inaccuracies described in the measurement methods also contribute to the imprecision of these values.

Capsicum chili peppers are commonly used to add pungency in cuisines worldwide. The range of pepper heat reflected by a Scoville score is from 500 or less (sweet peppers) to over 2.6 million (Pepper X) (table below; Scoville scales for individual chili peppers are in the respective linked article). Some peppers such as the Guntur chilli and Rocoto are excluded from the list due to their very wide SHU range. Others such as Dragon's Breath and Chocolate 7-pot have not been officially verified.{{cite web | title=Pepper X – Latest News and Information | website=Chili Pepper Madness|author= Mike Hultquist| date=23 February 2018 | url=https://www.chilipeppermadness.com/news/pepper-x-latest-news-and-information/ | access-date=21 January 2019}}{{cite web|url=https://www.nytimes.com/2022/08/18/t-magazine/hot-chiles-pepper-spice.html|title=How the Chile Became Hot|author=Ligaya Mishan|work=The New York Times|date=August 18, 2022|accessdate=September 1, 2022|quote=Carolina Reaper, known to reach as many as 2.2 million S.H.U.s — more potent than some pepper sprays — and certified by Guinness World Records as the hottest chile on earth.}}

File:Capsaicin pharmacophore.svg", the portion of the molecule that produces biological effects]]

The class of compounds causing pungency in plants such as chili peppers is called capsaicinoids, which display a linear correlation between concentration and Scoville scale, and may vary in content during ripening.{{cite journal|pmc=4606152|year=2015|last1=Nagy|first1=Z|title=Determination of Polyphenols, Capsaicinoids, and Vitamin C in New Hybrids of Chili Peppers|journal=Journal of Analytical Methods in Chemistry|volume=2015|pages=1–10|last2=Daood|first2=H|last3=Ambrózy|first3=Z|last4=Helyes|first4=L|doi=10.1155/2015/102125|pmid=26495153|doi-access=free}} Capsaicin is the major capsaicinoid in chili peppers.

The Scoville scale may be used to express the pungency of other, unrelated TRPV1 agonists, sometimes with extrapolation for much hotter compounds. One such substance is resiniferatoxin, an alkaloid present in the sap of some species of euphorbia plants (spurges). Since it is 1,000 times as hot as capsaicin, it would have a Scoville scale rating of 16 billion.{{cite book| last1= Atala| first1= Anthony| first2= Debra |last2= Slade | year= 2003| title= Bladder Disease| place= Washington, DC| publisher= National Bladder Foundation| page= 361| isbn= }} In the table below, non-capsaicinoid compounds are italicized.

• {{Portal inline|Food}}
• {{Portal inline|Chemistry}}
• List of capsaicinoids

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{{Taste}}

{{Chili peppers}}

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Category:1912 introductions

*Scoville scale

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